I have an old PS composites Venom, cut for around 15-16 stone. slalom seat removed and replaced with low profile foam mat and pads, I even made a lap block to reduce deck implosion. Its branded with AS watersports logo and in gold glitter.

Its a bit battered (cosmetically) but watertight and sound in the seams, £125 if anyone is interested. Based in W Yorkshire.

An excellent condition, union jack Downtime Whisper, its got a white hull and has built in screw in mounts in the bow for a go pro mount. Only thing is, as you rightly say, there are few boats around and with the demise of Downtime the ways of getting new boats are very few and far between. Ive had the Whisper in the attic as my spare for if I ever kill my Kor and if it stays up there thats fine by me. However if you want it £500 and its yours. If the price doesnt put you off I'll try and get some pictures for you.

Neill / mole
if the original poster isn't interested, or is too 'light' for it, then i have sent a pm expressing an interest.
otherwise
Chris,
as the op 500 is a bit high, i could stretch to 400 at the end of the month, providing i dont tell my wife, if you are interested
Thanks
Brian

There is a close up of damage to the hull, this has been repaired with epoxy and there is no soft spot, boat is nice and stiff throughout. Only down side is that a previous owner dribbled excess resin over deck when repairing the seam, cosmetic issue and the resin can be popped off with a knife if you can be arsed.

Hellbender is pretty immaculate. £450 ono : (Was my boat, but no longer able to paddle kayaks following spinal surgery)
Venom is older - sound and solid few scrapes from use but nothing major. two small chips to gelcoat on hull but nothing that'll leak £200 ono: (My wife's boat.)